Abstract:

Based on the flow characteristics of single-disc fully mixed flow and multiple fully mixed flow series in horizontal single-shaft rotating disc polycondensation reactor, coupled with the shear rheological model of copolyester, the complex reaction kinetics model based on functional group model and the diffusion mass transfer model of volatile small molecules, a disk-by-disk simulation of the polycondensation process of industrial-scale poly(1,4-cyclohexylene dimethylene terephthalate glycol) (PCTG) was realized. The co-polycondensation process and product variation within the conditions of reaction temperature of 270—285℃, pressure of 50—300Pa, residence time of 150—240min, disc rotation speed of 2—8r/min and production load of 150—300t/d were analyzed. The simulation results showed that the residence time was benefit by the increasing liquid level and the decreasing of the production load. The increasing disk rotation speed could accelerate the surface renewal of the melt. High temperature, low pressure, extended residence time and accelerated surface renewal all contributed to the increase of the degree of polymerization. The modeling and simulation of the polycondensation process of PCTG copolyester in this typical polycondensation reactor could predict the progress of polymerization reaction and product changes. It would help to solve the key problems of equipment design in the engineering of complex reaction systems for multi-component copolymerization in high-end copolyesters, and guide the engineering scaling up and production process control optimization of the polycondensation reactor.

Key words: polymerization reactor, copolyester, 1,4-cyclohexanedimethanol, mass transfer, simulation

摘要：

根据卧式单轴圆盘缩聚反应器单盘全混流、全釜多个全混流串联的流动特性，通过共聚酯剪切流变模型、基于官能团模型的复杂反应动力学模型以及挥发性小分子的扩散传质模型耦合，实现了工业规模聚对苯二甲酸乙二醇-1,4-环己烷二甲醇酯（PCTG）缩聚过程的逐盘模拟仿真，并分析了反应温度270~285℃、压力50~300Pa、停留时间150~240min、圆盘转速2~8r/min、生产负荷150~300t/d条件范围内的共缩聚过程及产物变化规律。模拟结果表明，提高液位或降低负荷均可增加熔体停留时间，提高圆盘转速可加快熔体表面更新；高温、低压、增加停留时间和加快表面更新的操作均有利于提高共聚酯PCTG的聚合度。该典型缩聚反应器中PCTG共聚酯的缩聚过程建模和模拟仿真可预测聚合反应进度和产品变化，有助于解决高端共聚酯中多元共聚复杂反应体系工程化中关键装备设计难题，指导缩聚反应器的工程放大和生产过程控制优化。

关键词: 缩聚反应器, 共聚酯, 1,4-环己烷二甲醇, 传质, 模拟